Summary In the United States, many young, emerging Spanish-English bilingual children only have access to Spanish in their home environment, and of these, nearly 10% are expected to have speech sound disorder (SSD), a high-incidence disability negatively impacting their language, academic, social, and occupational outcomes. Early treatment of SSD for these young bilingual children requires treatment in their first language, which is known to support development of both Spanish and English as they develop bilingually. However, the evidence base to support efficient treatment in Spanish for bilingual children currently does not exist, despite the availability of evidence-based options for monolingual English-speaking children. This is an unacceptable gap in the literature amounting to a significant health disparity between monolingual and bilingual children. To address this disparity directly, we attend to the initial step in treatment of SSD?selection of the speech sounds trained during treatment sessions. Evidence from monolinguals has shown that complex targets result in faster learning of sounds beyond the trained target. Drawing from this evidence, we examine the complexity of consonant clusters (e.g., /fl/ in flan or /b?/ in brinca) in the Spanish productions of typically developing bilingual children to determine which are phonetically and phonologically most complex. We also evaluate an outcome-based, hypothesis-driven intervention to determine if consonant cluster stimuli (e.g., /fl/ in flan) result in different treatment outcomes than singleton consonant stimuli (e.g., /l/ in lindo) in emerging bilinguals with SSD. With this project we seek to reduce the health disparity between bilingual and monolingual children by offering empirical data to support efficacious treatment target selection in Spanish-speaking bilingual children. This proposal contains training components in the skills and experience necessary to excel as an independent research scientist conducting investigations with direct clinical impact on health disparities affecting Spanish-English bilingual children. Training will take place at San Diego State University under the mentorship and supervision of university faculty and a local speech- language pathologist.